Microstructure Evolution and Properties of WC/Ni Based Coating on the Surface of 12CrMoV Alloy Steel by Laser Cladding
To solve the problems of wear and corrosion failure in cold-working die steel during long-term service,Ni60 coatings with different WC contents are prepared on 12CrMoV substrate using laser cladding technology.The forming characteristics,microstructure,mechanical properties,and corrosion resistance of the coatings are characterized using X-ray diffraction,scanning electron microscopy,energy dispersive spectroscopy,friction and wear testing machines,and electrochemical workstations.The results indicate that the additive amount of the WC can change the solidification characteristics of the melt pool,thereby reducing the width of the coatings and increasing the depth of the coatings.When the additive amount of the WC is 30%(mass fraction),the hardness of the coating is 853 HV0.3,and the average friction coefficient is only 0.467.It has excellent mechanical properties,but the toughness of the coating decreases,leading to the formation of pores during the solidification process,which reduces the corrosion resistance of the coating.When the additive amount of the WC is 10%and 20%respectively,the size of the grain structure is refined,the grain boundary area is reduced,and it has excellent corrosion resistance.When the additive amount of the WC is 20%,the corrosion current density of the coating is only 3.65×10-5 A/cm2,and the mechanical properties are only slightly lower than the coating obtained with 30%WC additions.Therefore,this study explored suitable WC/Ni60 coatings for wear and corrosion environments,determined the optimal additive amount of the WC,expanded the application range of WC/Ni60 coatings in mold steel,and has guiding significance for engineering practice.
NETL
NSTL
万方数据
